Fast-acting parachutes



Dec. 20, 1960 F. B. STENCEL FAST-ACTING PARACHUTES 3 Sheets-Sheet 1 Filed Feb. 28, 1958 INVENTOR.

FRED B. STENCEL A TTORNE Y Dec. 20, 1960 F. B. STENCEL 2,965,337

FAST-ACTING PARACHUTES Filed Feb. 28, 1958 3 Sheets-Sheet 2 INVENTOR FRED B STEN CEL Ea AM ATTORNEY Dec. 20, 1960 F. B. STENCEL 2,965,337

FAST-ACTING PARACHUTES Filed Feb. 28, 1958 3 Sheets-Sheet 3 IN VENTOR FRED B. STENCEL ATTORNE 2,965,33i FAST-ACTING PARACHUTES Fred B. Stencel, Ash'eville', N.C.', assignor to A'incel Propulsion Inc;, a corporation of Delaware Filed Feb. 28, 1958, Set. No. 718,364 Claims. (Cl. 244- 147) United States Patent i chute, a novel and effective projecting means so constructed as to project the projected assembly in a predetermined direction at a high rate of speed, so that the total projected flight time is as short as 0.3 second.

A further object is to devise a simple and effective explosive projection means, for parachutes of the type referred to, including novel means for confining the explosion gases: during the initial movement of the projected assembly. in such fashion as to make more effective use of the explosive means employed. i Another object is to provide, in such a projection means relatively gradual, release of the explosion gases.

Yet another object is to provide projection'means including a projection tube, an explosive charge situated within thetube, and an actuating assembly for the explosive charge, with the actuating assembly mounted on the end of the tube adjacent the charge and closing such end of the tube in a novel fashion.

.A still further object is toprovide, insuch apparatus, actuating means for the explosivecharge, which actuating means includes a triggering device which also acts as a safety latch, such device being necessarily placed in safe position before arming.

Another object is to provide in such a projection assembly an actuating means which can be completely assembled with the triggering device in safe position, before being mounted in its operative'position with respect to the explosive charge which itis to actuate.

, In order that the manner in which these and other objects are attained in accordance :with the invention can be understood in detail, reference is had to the accompanying drawings, which form a part of this specification, and wherein: r

Fig. 1 is a vertical sectional view, with some parts shown in elevation and others broken away for clarity, of a parachute in accordance with one embodiment of the invention; i

Fig. 2 is a detailed vertical sectional view of the projecting means of the apparatus of Fig. l, on enlarged scale and showing the same in unfired condition, and

a. novel arrangement for assuring a sudden, rather than Fig. 3 is a view like Fig. 2 but illustrating the projecting I mean? Patented Dec. 20, 1980 Tube 3 telescopically embraces the projecting tube 6 of the projecting assembly 2. The lower end of tube 3 abuts the upper surface of a flange 7 which forms a part of tube 6fa'nd is located on the lower or trailing end portion thereof. The lower end portion of tube 3 is provided with a transverse internal groove 8 in which is disposed an O-ring 9 to provide a substantially fluid-tight seal between tubes 3 and 6. v A V Projecting tube 6 is secured to the mounting structure indicated generally at 10. The mounting structure 10 in turn is secured to any suitable supporting structure (not shown) before projection of the projected assembly, only the top wall 11 and side walls 12 of the mounting structure being shown in the drawings. In addition to mounting the projection means, structure 10 also serves to protect that portion of the projecting assembly 2 located below the top wall 11, as hereafter explained.

The lower end portion of projecting tube 6 passes through an opening provided in top wall 11 of mounting structure 10. The lower surface of flange 7 of tube 6 abuts a retaining plate 13 below which is disposed a spacer 14, the lower surface of spacer 14 being seated against the upper face of top wall 11. Tube 6 then passes through an opening in a latch plate 15 which is disposed adjacent and below top wall 11. The lower end portion of tube 6 is threaded so as to receive lock nut 16 which is brought into contact with the lower surface of plate 15 to retain the same in place. Projecting tube 6 is thus rigidly secured to mounting structure 10.

Positioned within projecting tube 6 is a combustion chamber 17. The outer diameter of the lower portion 18 of chamber 17 is the same as the inner diameter of tube '6. Combustion chamber 17 is provided with a bottom end flange 19, the upper surface of which abuts the lower end of tube 6. The combustion chamber 17 is generally in the form of a hollow cylinder, and has an upper portion 20 of smaller outer diameter than the lower portion 18. The upper portion 20 is closed at its free end and the wall of the upper portion is provided with a plurality of perforations 21.

An explosive charge container 22 with an outer diameter equal to the inner diameter of lower portion 18 of chamber 17 is positioned within the lower portion 18. Container 22 is provided with a base flange 23 which abuts the lower surface of end flange 19 of chamber 17. A deformable closure plate 24serves to close the upper end of container 22, the peripheral portion of plate 24 engaging the upper end of the container. A rod 25 of small diameter, secured in any suitable fashion, to the closed upper end of chamber 17, is of such length as to have its lower end abutting the upper surface of plate 24, at the center thereof, when container 22 is in place within chamber 17. Rod 25 thus serves to hold plate 24 in position against the top of container 22. An explosive charge 26 is enclosed within container 22. Below charge 26, container 22 also mounts a primer 27 coaxially aligned with projecting tube '6, the lower end of primer 27 extending slightly below flange 23.

A firing pin assembly, indicated generally at 23, is positioned below primer 27 and container 22. The housing for the firing pin assembly 28 is a tubular member or sleeve 29 having an upper end flange 3G'held in abutting relation with the lower surface of end flange 23 of container 22 by a cap nut 31 threaded to the lower end of projecting tube 6. Nut 31 has an inwardly directed flange 32 at its lower end which abuts the lower surface of end 1 flange 30 of sleeve 29.

The upper end of sleeve 29 houses a firing pin 33 slidably disposed within a plug 34. A retaining screw 34 holds plug 34 in place. The upper end of firing pin 33 is positioned within a bore 35 in plug 34 and aligned with the primer. The bore 35 is of increased diameter at its lower end, so as to receive a flange 36 on firing pin 33. At the lower end of bore 35, plug 34 is provided with a transverse annular groove 37. With the firing pin positioned so that theflange 36 is disposed within the lower portion of bore 35 and above groove 37, a retaining ring is placed within groove 37 and extends into bore 35 to prevent withdrawal of the firing pin. The length of the lower enlarged portion of bore 35 above groove 37 is greater than the width of flange 36 measured in the axial direction ofmember '29 by an amount suificient to allow movement of firing pin 33 into'engagement with primer 27, the length of the portion of firing pin 33 above flange 36 being sufiicient to enable the firing pin to contact primer 27 when the firing pin is suddenly urged upwardly. The portion of the firing pin 33 below flange 36 extends slightly below the end of plug 34 when the pin 33 is in its uppermost position.

Disposed within sleeve 29 and below the lower end of firing pin 33 is a firing pin actuating plunger 38. Plunger 38 has an upper portion of such diameter as to allow free axial movement of the plunger within sleeve 29. The lower portion of the plunger 38 is of smaller diameter than the upper portion so as to form shoulder 39 and permit a spring 40 to be disposed between the lower portion of plunger 38 and the inner surface of sleeve 29. The lower end portion of sleeve 29 is threaded to receive a cap nut 41, which nut has a hole 42 through its transverse wall to accommodate the lower end portion of plunger 38. Cap nut 41 thus provides a transverse shoulder against which one end of spring 40 engages. Spring 40 is therefore disposed between the transverse wall of cap nut 41 and the shoulder 39 of plunger 38.

The lower portion of sleeve 29 i provided with a radially directed aperture 43 through which the tip of a Bowden wire 44 extends. The Bowden wire 44 is brought to the sleeve 29 via an opening 46 in one of the walls 12 of the mounting structure and adapter 45 mounted on sleeve 29 at aperture 43. The adapter 45, in addition 'to providing bore 47 to guide the tip of Bowden wire 44 to aperture 43, also serves as a means for securing the tip of the sheath (not shown) of the Bowden wire 44.

The upper portion of plunger 38 is provided with a peripheral transverse groove 48. Prior to placing the spring 40 within member 29, the plunger 38 is so posi= tion'ed that the groove 48 is aligned with aperture 43. The Bowden wire 44 is then inserted through aperture 43 and passes around and within a portionof groove 48. This positions plunger 38 relative to the lower end of sleeve 29 so that spring 40'will be compressed when placed within sleeve 29 and the 'cap nut 4 is threaded to the lower end of sleeve 29. Bowden wire 44 is engaged within groove 48 sufficiently to prevent movement of plunger 38 by the force of spring 40. Groove 48 is employed, rather than using an aperture, in order to'simvplify the problem of properly positioning the plunger with respect to aperture 43 preparatory to insertion of'the Bowden wire.

' It will be noted that the lower end of projection tube '6, and the entire firing pin actuator assembly, are confined within a space defined by the top wall and side Walls of the mounting structure 10.

Plate 13 serves as a means by which the lower end of acontainer in the form of a flexible outer bag 49 can be fixed to the mounting means for temporarily housing the projected assembly 1. The lower portion of bag 49 includes an opening whereby the lower edge or bottom of bag 49 is secured under a dependent flange, at the periphery of plate 13, as by a draw cord arrangement in the manner described in my aforementioned application Serial Number 718,362, so that the bottom of the outer bag is fixedly attached to the projection tube at a point above and adjacent the top wall 11. The upper edge of bag 49 is de tachably secured to the dependent flange 50 of a cover plate 51 which is fixedly secured to the top of the .projected assembly 1 by a cap screw 52. Consequently,

when the projected assembly 1 is projected, the lower end of bag 49 is retained by plate 13 and the upper end of bag 49 slips off flange 50 so that the bag is retained on the mounting structure. 7

Prior to operation, the projected assembly 1, projecting assembly 2 and mounting structure 10 are placed in assembled relation as shown in Figs. 1 and 2. Operation of the projecting assembly 2 is initiated by withdrawal of Bowden wire '44 from engagement with plunger 38. This allows the spring 40 to expand, moving the-plunger rapidly into contact with the lower end of firing pin 33. The firing pin strikes the primer 27, which is thus ignited and which in turn ignites the charge 26 in container 22. The explosion gases produced .f'o-rce the'deformable closure plate upwardly and around the lower tip of rod 25. The gases then pass into the upper portion of chamber 17 and thence through the perforations 21 and into tubes 3 and 6 Since projectiletube 3 is closed at its upper end by deployment means 5 and a substantially fluidtight seal is: maintained between tubes 3 and 6 by the O-ring 9 at the lower end of tube 3, the expanding explosion gases force the projected assembly to travel away from the projecting assembly. Since the O-ring 9 is disposed atthe lower end of tube 3, the seal is eflective during. the travel of the projected assembly 1 for that length of tube 6 determined by the spacing between the position in a certain direction away from the object on which the assembly. is mounted. V

Deformable cover plate 24, with its associated rod '25, forms means operative to suddenly release the explosion gases from. container- 22 into the combustion chamber 17 at a time,usubsequent to actual ignition of charge 26, when a predetermined amount of pressure has been built up with container 22. The extent of the time lag be tween ignition of the charge and release of the explosion gases into. the combustion chamber is of course determined by the thickness of plate 724, the material from which it is fashioned, and the dimensions of the plate and the top of container 22.

It will be noted thatthe combination of Bowden wire 44 and the groove 48 in plunger 38 constitutes not only a triggering device for the firing pin actuating means, but

alsoa safety device retaining plunger 38 against movement toward primer 27 under all conditions save removal of the Bowden wire from engagement with the groove 48. vIt is also to be noted that, if the device is armed after attachment of sleeve 29 to projection tube 6, spring 40 is not compressed, to store therein the energy necessary to actuate the firing pin, unless the tip of-the Bowden wire is first engaged in groove 48. Thus, the device is conditioned to safety even before it is made operative to explo-dethe primer. Finally, it will be understood trat the entire actuator assembly, including all parts carried by' sleeve 29, can be assembled and readied for actuation before attachment to the projection tube 6, so affording additional assurance against accidental premature discharge of the projection means. i

I claim:

1. Ina parachute of the type comprising a projected assembly including an elongated projectile and a folded canopy carried thereby, the combination with said projected assembly of a projection and mounting assembly comp-rising'a projection tube having a base portion and a portion with which said projectile is adapted to be telescopically engaged,.a tubular member extending within said baseportion and defining a combustion chamber, the end portion of said tubular member innermost with respect to said projection tube being laterally perforated, a charge container disposed in the other end portion of said tubular member, said charge container having an open top directed toward said laterally perforated end portion, a deformable closure plate seated on the open top of said charge container, a hold-down rod secured to the perforated end portion of said tubular member and extending within said tubular member into engagement with the center of said closure plate to hold the plate against said charge container, an explosive charge disposed within said charge container, and means mounted on said projection tube and operatively associated with said charge to explode the same, said closure plate bemg effective to retain the explosion gases, resulting from explosion of said charge, within said container until the pressure within said container is sufficient to bend the outer portions of said closure plate toward the perforated end portion of said tubular member.

2. In a parachute of the type comprising a projected assembly including an elongated projectile and a folded canopy carried thereby, the combination of a projection and mounting assembly comprising a mounting plate provided with an opening, a projection tube having a base portion extending through said opening and a portion extending away from said plate and with which said projectile is telescopically engaged, means securing said projection tube to said mounting plate, a retaining plate having an opening through which said projection tube extends, said retaining plate being secured to said projection tube and disposed adjacent to said mounting plate on the side thereof facing the projected assembly, a flexible outer bag enclosing said projected assembly and from which the latter is to be projected, the bottom end of said outer bag being secured to said retaining plate, explosive means disposed in the base portion of said projection tube, and actuating means mounted on the base portion of said projection tube and operatively associated with said explosive means to explode the same.

3. The device of claim 1 comprising sealing means disposed between the projectile and said projection tube to provide a seal during projection of the projectile from said projection tube.

4. In a parachute, the combination of a mounting plate having an opening therein, a projection tube extending through said opening and having a free tip spaced from said plate on one side thereof and a base portion disposed adjacent said plate, means securing said tube to said plate, tubular means disposed within said base portion and defining a combustion chamber communicating with the interior of said tube, said tubular means including an end flange abutting the adjacent end of said projection tube, explosive means disposed within said combustion chamber and including an explosive charge and an impact-actuated primer therefor, said explosive means including a charge container having a flange abutting said end flange, a firing pin assembly axially aligned with said base portion of said projection tube and including a firing pin opcrably disposed with respect to said primer, said firing pin assembly comprising a tubular housing having an end flange engaging the flange of said charge container, and means threadably engaged with said base portion of said projection tube and effective to clamp said firing pin assembly to said projection tube, sa.d threadably engaged means'being a cap nut having a flange engaged with the flange of said tubular housing.

5. In a parachute of the type comprising a projection parachute assembly including a folding canopy carried by an elongated projectile, the combination with the projected parachute assembly of mounting and projection means comprising a housing having side walls and a top Wall with an opening therein; a projection tube having a lower end portion extending through said opening and terminating within said housing, said projection tube being telescopically engaged with the projectile of the projection assembly above sa.d top wall; means rigidly securing said projection tube to said top wall; explosive means disposed within the lower end portion of said projection tube and including an explosive charge and a primer therefor; a firing pin assembly disposed within said housing in operative relation with said primer; means within said housing operatively engaged with the bottom end of said projection. tube and with said firing pin assembly to secure the latter to said tube; a flexible outer bag enclosing the projected assembly; and means attaching the bottom of said outer bag fixedly to said projection tube at a point above and adjacent said top wall of said housing.

References Cited in the file of this patent UNITED STATES PATENTS 1,081,137 Von Augezd Dec. 9, 1913 2,309,978 Pratt Feb. 2, 1943 2,650,540 Bugg Sept. 1, 1953 2,673,051 Frost Mar. 23, 1954 2,736,236 Martin Feb. 28, 1956 FOREIGN PATENTS 436,529 France Jan. 25, 1912 

